Stabilization of 2-thenyl chloride



Patented Dec. 21, 1948 STABILIZATION OF Z-THENYL CHLORIDE Ferdinand B. Zienty, St. Louis, Mo., assignor to Monsanto Chemical Company, St. Louis, Mo., a corporation of Delaware No Drawing. Application October 18, 1946, Serial No. 704,287

16 Claims. 1

' This invention relates to the stabilization of 2-theny1 chloride and more particularly to a novel composition comprising 2-thenyl chloride and a stabilizer therefor.

'2-thenyl chloride is potentially a very useful intermediate because of its great reactivity and resemblance in certain respects to benzyl chloride. However, unlike benzyl chloride, 2-thenyl chloride is relatively unstable at normal and subnormal temperatures, and storage of the material at room temperature or at lower temperature is unfeasible because the material resinifles very readily to form a black resin. Even the storage of 2-theny1 chloride at C. or below does not avoid this decomposition. Moreover, 2-thenyl chloride is highly reactive and combines readily with a large number of basic substances such as aniline, methyl aniline, dimethyl aniline, trimethyl amine, pyridine, and other amines, thereby depleting the Z-thenyl chloride and rendering it unavailable for desired reactions.

- One of the objects of the present invention is to provide a novelcomposition comprising Z-thenyl chloride having incorporated therein certain amines which stabilize the 2-thenyl chloride substantially without depleting the activity of the Z-thenyl chloride.

Another object is to provide a nove1 method for stabilizing 2-thenyl chloride.

Further objects will become apparent from the following description and examples.

According to the present invention, generally stated, a composition exhibiting marked stability at normal and subnormal temperatures and having the full activity of freshly prepared Z-thenyl chloride is provided by incorporating with 2- thenyl chloride 0.55%, or even more, for example -15%, and desirably 1-2% by weight of an amine having the formula:

in which R represents hydrogen, alkyl, cycloalkyl, or aralkyl radicals, and R1 and R2 each represent an alkyl radical containing at least 8 carbon atoms, a cycloalkyl radical containing at least 5 carbon atoms in its ring structure or an aralkyl radical, R1 and R2 being similar or dissimilar radicals, provided, however, that when R is hydrogen and R1 and R2 are alkyl radicals, the R1 and R2 must each contain at least 10 carbon atoms.

In order to provide maximum stability in the composition of the present invention, it is desirableto eliminate from the 2-theny1 chloride sub- 2 stantially all of the free acidity which may be present therein and also to render the material substantially anhydrous, for example, to the eX-- tent ofcontaining less than 0.5% moisture and desirably less than 0.2% moisture. This may be accomplished, for example, by washing 2-theny1 chloride with a cold aqueous solution containing 5% by Weight of sodium bicarbonate, thereafter washing the Z-thenyl chloride with cold water, for example, ice water, and recovering the Z-thenyl chloride in substantially anhydrous form by fractional distillation under reduced pressure. To the fractionally distilled 2-thenyl chloride is added an amine of the aforescribed type in amounts as hereinbefore described.

The Z-thenyl chloride composition thus obtained has been found to be stable for more than 9 months at 5 0., more than 3 months at 25 0., and as long as 3 months at 42 C. Moreover, the Z-thenyl chloride composition thus prepared has been found to possess substantially the reactivity of freshly distilled 2-thenyl chloride and may be employed in chemical reactions in substantially the stoichiometric amounts based upon the content of Z-thenyl chloride employed in the preparation of the composition of the present invention. Illustrative of the amines suitable for. the preparation of the novel composition of the present invention, are dicyclohexylamine, a mixture of N-alkyl-N-benzyl"cyclohexylamines in which the alkyl radicals contain 8 to 18 carbonatoms, a mixture of N-alkyl-dicy.clohexylamines in which the alkyl radicals contain 8 to 18 carbon atoms, a mixture of N-alkyl-dibenzylamines in which the alkyl radicals contain 8 to 18 carbon atoms, N- methyl-dicyclohexylamine, N-methyl-dibenzylamine, dibenzylamine, didodecylamine, Nmethyldioctylamine, N 2 ethylhexyl) dicyclopentylamine, N methyl dicyclopentylamine, N (2- ethylhexyl) dicyclohexylamine, N (2 ethyh hexyl) dibenzylamine, N methyl dinaphthylmethyl amines, and di-(cyclohexyl-cyclohexyl)- amine.

The following examples will serve to illustrate the novel compositions of the present invention and the preparation thereof. These examples are to be construed merely as illustrative and not as limiting the present invention except as defined in the appended claims.

Example I A quantity of 2-thenyl chloride was washed with cold 5% sodium bicarbonate solution to remove free acidity. The washed material was then washed with ice Water and fractionally distively 0.5%, 2%, 5%, and iby weight of dicyclohexylamine. In each instance, a composition stable at temperatures ranging rom.) 42 C. for periods of time ranging from more than 3 months to more than 9 months were obtained.

Example II :To ;respective portions of a quantity of *freshly distilled acid-free substantially anhydrous 2- thenyl ;chloride were .added 0.5%, 1%, 2%, and 5% by weight of -;a=mixture of N-alkyl-N-benzylcyclohexylamines :in which the alkyl groups ranged from.8 to 18 carbon atoms. The resulting compositions were found to be stable at 5 C. for more than 9 months with substantially no tendency toward resinification.

Example III To respective portions of freshly-distilled acidfree substantially anhydrous 2-thenyl chloride was added 2% by Weight of one of the following amines; N-methyl-dioctylamine, didodecylamine, N-- methyl dicyclopentylamine, and dibenzylamine. The samples showed definite, marked stability against resinification but were not as thoroughly stabilized as the samples prepared in Example I. The compositions thus prepared can be stored at 5 C. for as long as 4 weeks without resinification.

Example V To respective portions of freshly-distilled acidfree substantially anhydrous 2-thenyl chloride was added 2% of one of the following amines: N (2 ethylhexyl) dibenzylamine, N-'-(2-ethylhexyl) -dicyclopentylamine, N- ('2-ethylhexyl) -dicyclohexylamine, N-methyl-di-(alpha-naphthylmethyl) amine, and N benzyl dioctylamine. Only a light brown color developed in the composition on prolonged storage, for example, at 25 C. for several months or longer. There was -no evidence of resinification in the composition.

Example VI For the purpose of the following preparation, a quantity of 2-thenyl chloride was employed which had been stored after preparation for 3 days at 5 C. This materialhad developedsome free acidity. To a quantity ofthis material was added 1% by weight of dicyclohexylamine. The resu in c m it on wa ound t possess-ap- .dis-tilled chloride containing a trace or less of free acidity, have been found to be entirely satisfactory for proximately or less of the stability of a corresponding composition prepared from freshly distilled, acid-washed, substantially anhydrous Z-thenyl chloride and 1% of dicyclohexylamine. This stability was ascertained by the appearance of the sample over several weeks time in storage at :5 C. It :has {been found feasible "to {utilize a composition of this type .in those instances in which a stock of Z-thenyl chloride is to be em- ;ployed in chemical reactions within a few weeks .of ,the time at which the 2-thenyl chloride is prepared.

The novelcompositions of the present invention, particularly \When prepared from freshly substantially anhydrous 2 thenyl use in chemical reactions without distilling the composition prior to such use. With the possible exception of a few instances in which the presence .of the stabilizer might be considered igndesirable gin a reaction mixture involving ,2-rthenyl chloride, it -1is;;unnecessary -to fractionate theeopb position of the present inventionprior todtsruse in greactions. If such fractionation is. deemed .desirable, it has been found that -;the re -r i s substantially no evidence of a high boiling residue .;in the distillation flask after {the distillation .ofran-y of -.;the compositions of the present invention. This is additional evidence of the substantial a bsence of any tendency toward resinifica tiong-of the no e com osit n of t pre t nve t on.

Example *VII ,A quantity .of ,Z-thenyl chloride was washed with a cold 5% aqueous solution of sodium bi.- carbonate and then with .cold water until substaritially neutral. The material was then .dried over calcium chloride. To the dried, .acidsfree Z-thenylchloride was added 2% of zdicyclohexylamine. The resulting composition was foundto be substantially free from resinification at the end. of 9-monthsof .stora ge.at. 5 .C.

-Lclaim:

l- Astable ,composition consisting ,ofz-thenyl chloride and a smallportion of anlarninepfithe formula type:

R1 RI I-.R2

in which R represents a' radical selected from the group consistin .of hydrogen, alkyl, xcycloalkyl, and'aralkyl radicals, R1 and Raeachrepresent a radical selected from the group :consisting of alkyl radicals containing at least :8 carbon atoms, cycloalkyl radicals containin at least :5 carbon atoms in their ring structure and aralkyl radicals.

12. A stablecomposition consisting ,of :2-thenyl chloride and at least 0.5% of an amine of the formula type:

R 1 RI I-R 2 in which R represents a radical selected from the group consisting of hydrogen, alkyl, cycloallryl, and aralkyl radicals, R1 and R2 each'repr'esent a radical selected from the group consisting-of alkyl radicals containing at leastB carbon atoms, cycloalkyl radicals containing at least 5 carbon atoms in'their ring structure and aralkyltradicals.

:3. A stable composition consisting of 2-thenyl chlpride and 0.5'5% of an amine of the formula type:

R1 Rl T-IR2 in which it represents a radical selected :fromathe group consisting of hydrogen, alkyl, cycloalkyl, and aralkyl radicals, R1 and R2 each represent a radical selected from the group consisting of alkyl radicals containing at least 8 carbon atoms, cycloalkyl radicals containing at least 5 carbon atoms in their ring structure and aralkyl radicals.

4. A stable composition consisting of Z-thenyl chloride and 05-10% of an amine of the formula type:

R! R-1 IR2 in which R represents a radical selected from the group consisting of hydrogen, alkyl, cycloalkyl, and aralkyl radicals, R1 and R2 each represent a radical selected from the group consisting of alkyl radicals containing at least 8 carbon atoms, cycloalkyl radicals containing at least 5 carbon atoms in their ring structure and aralkyl radicals.

5. A stable composition consisting of 2-theny1 chloride and 12% of an amine of the formula type:

R1 RI IRz in which R represents a radical selected from the group consisting of hydrogen, alkyl, cycloalkyl, and aralkyl radicals, R1 and R2 each represent a radical selected from the group consisting of alkyl radicals containing at least 8 carbon atoms, cycloalkyl radicals containing at least 5 carbon atoms in their ring structure and aralkyl radicals.

6. A stable composition consistin of 2-thenyl chloride and at least 0.5% of dicyclohexylamine.

'7. A stable composition consisting of 2-thenyl chloride and 1-2% of dicyclohexylamine.

8. A stable composition consisting of Z-thenyl chloride and at least 0.5% of a mixture of N- alkyl-N-benzyl-cyclohexylamines in which the alkyl groups range from 8 to 18 carbon atoms.

9. A stable composition consisting of Z-thenyl chloride and at least 0.5% of a mixture of N alkyl-dicyclohexylamines in which the alkyl groups range from 8 to 18 carbon atoms.

10. A process of stabilizing 2-thenyl chloride comprising incorporating therein a small portion of an amine of the formula type:

in Which R represents a radical selected from the group consisting of hydrogen, alkyl, cycloalkyl, and aralkyl radicals, R1 and R2 each represent a radical selected from the group consisting of alkyl radicals containing at least 8 carbon atoms, cycloalkyl radicals containing at least 5 carbon atoms in their ring structure and aralkyl radicals,

11. A process of stabilizing Z-thenyl chloride comprising incorporating therein at least 0.5% of an amine of the formula type:

R1 R-Ih-R:

in which R represents a radical selected from the group consisting of hydrogen, alkyl, cycloalkyl, and aralkyl radicals, R1 and R2 each represent a radical selected from the group consisting of alkyl radicals containing at least 8 carbon atoms, cycloalkyl radicals containing at least 5 carbon atoms in their ring structure and aralkyl radicals.

12. A process of stabilizing 2-thenyl chloride comprising incorporating in substantially neutral, freshly distilled 2-thenyl chloride a small portion of an amine of the formula type:

R1 R-Ik-Rz in which R represents a radical selected from the group consisting of hydrogen, alkyl, cycloalkyl, and aralkyl radicals, R1 and R2 each represent a radical selected from the group consisting of alkyl radicals containing at least 8 carbon atoms, cycloalkyl radicals containing at least 5 carbon atoms in their ring structure and aralkyl radicals.

13. A process of stabilizing 2-thenyl chloride comprising incorporating in substantially neutral, freshly distilled 2-thenyl chloride at least 0.5% of dicyclohexylamine.

14. A process of stabilizing 2-thenyl chloride comprising adding to substantially neutral and salt free, freshly distilled 2-thenyl chloride a small quantity of an amine of the formula type:

R1 RII\TR2 in which R represents a radical selected from the group consisting of hydrogen, alkyl, cycloalkyl, and aralkyl radicals, R1 and R2 each represent a radical selected from the group consisting of alkyl radicals containing at least 8 carbon atoms, cycloalkyl radicals containing at least 5 carbon atoms in their ring structure and aralkyl radicals.

15. A process of stabilizing Z-thenyl chloride comprising adding to substantially neutral and salt free, anhydrous 2-thenyl chloride at least 0.5% of an amine of the formula type:

in which R represents a radical selected from the group consisting of hydrogen, alkyl, cycloalkyl, and aralkyl radicals, R1 and R2 each represent a radical selected from the group consisting of alkyl radicals containing at least 8 carbon atoms, cycloalkyl radicals containing at least 5 carbon atoms in their ring structure and aralkyl radicals.

16. A process of stabilizing Z-thenyl chloride comprising adding to substantially neutral and salt free, freshly distilled 2-thenyl chloride at least 0.5% of an amine of the formula type:

in which R represents a radical selected from the group consisting of hydrogen, alkyl, cycloalkyl, and aralkyl radicals, R1 and R2 each represent a radical selected from the group consisting of alkyl radicals containing at least 8 carbon atoms, cycloalkyl radicals containing at least 5 carbon atoms in their ring structure and aralkyl radicals.

FERDINAND B. ZIENTY.

REFERENCES CITED Chemical Abstracts, 20: 390 (192 

